This may be the Webb’s finest image since taking office.
Like all scientists, astronomers obviously have a duty of objectivity; but that does not prevent them from having their favorites. We can for example cite 30 Doradus, a galaxy particularly courted by specialists. She is excessively tall; it is one of the largest known nebulae, almost 1900 light years long! It’s also very photogenic, thanks in part to its long wisps of dust that have earned it the nickname the Tarantula Nebula.
But it is another element of this object that interests researchers today. The James Webb Space Telescope has just revealed the most interesting part, the one that had remained invisible to the eyes of all the other telescopes: the heart of this stellar nurserywith the tens of thousands of juvenile stars it contains.
Usually this area is obscured by a thick cloud of cosmic dust. This is an almost insurmountable obstacle for the majority of telescopes, including good old Hubble. The latter had already captured stunning images of the Tarantula; but his instruments, designed to capture visible light and UV, did not allow him to pierce this veil of dust.
The heart of the Tarantula finally revealed
On the other hand, it is child’s play for the infrared eyes of the James Webb. Thanks to its Near-Infrared Camera (NIRCam)he made a remarkable discovery: a large cavity never seen before, housed in the middle of the nebula. This one would have been “dug out” by overpowering radiations which come from a large cluster of stars. These latter are visible in blue in the image of the JWST.
Only the denser areas have resisted this erosion caused by the stellar winds. This material forms sorts of pillars which are the most active areas of this nursery; it is there that the protostars are born which will eventually emerge from their cocoon of dust to join their fellows. The researchers even surprised a star in the middle of this maturation process, which would have been completely impossible without such an exceptional tool as the JWST.
One of the observatory’s other main instruments, the Mid-infrared Instrument (MIRI), has also brought its stone to the building. It operates at a different wavelength than the NIRCam, so it captured a very different image from the first. Here, the objective is not to observe the heart of the nebula, but the immense cloud of dust and gas which surrounds it, in blue and purple on this image. The red and orange lights correspond to hydrocarbons which are present in abundance in certain regions.
An exceptional window on the “cosmic noon“
In addition to being visually stunning, these pictures are also full of information that scientists can exploit; it’s not every day that they can work on such precise and instructive images of one of the most fascinating objects in the cosmos.
If the Tarantula interests astronomers so much, it is a rather singular object. Its chemical composition, for example, is very different from those of star nurseries found in the Milky Way. On the other hand, it is surprisingly similar to that of the gigantic star factories that existed at the time of the “cosmic noon” (“cosmic noon”). This is a crucial period in the history of our universe when stars were being produced at a daunting rate.
The Tarantula Nebula also exhibits this peculiarity; stars are born there in industrial quantities, far beyond anything that can be observed in our cosmic backyard. Luckily, it is also relatively close to our galaxy (barely 160,000 light-years). It has therefore gradually been transformed into a large open-air laboratory where specialists can study the dynamics of the universe during this famous “Cosmic noon” in excellent conditions.
It was therefore already a fascinating object of study, because the process of star formation is one of the most important elements in the dynamics of the cosmos. Understanding this phenomenon would allow researchers to make immense progress in their overall understanding of the universe.
And it’s all the more true now that the James Webb has opened this scientific gift package that has remained closed for ages. “The Webb has already begun to reveal a universe we’ve never seen before, and it’s only just beginning to rewrite the history of star formation.“, concludes the statement from NASA.